The present application relates to vehicle heating, ventilation and air conditioning (HVAC) systems. In particular, the present application relates to an air flow control member used to influence air flow through a vehicle HVAC system.
Vehicle HVAC systems may include cabin controls that are used by a vehicle occupant to control the output temperature and airflow of the air being delivered into the vehicle cabin from the HVAC system. It may be desirable to configure an HVAC system to provide a linear relationship between the position of a temperature controller and the output temperature. For example, when the controller is in a position half way between the coldest and hottest settings, the output temperature may be about half way between the coldest and hottest output temperatures. One way of increasing the linearity of the relationship between controller position and output temperature is to position a baffle in the air flow to adjust the airflow characteristics of the system. In some systems that utilize a pivoting temperature door to direct a portion of the air flow over a heater core, a baffle may be positioned in the arc of the temperature doors travel as it moves from one setting to another.
Such HVAC systems often drive air over an evaporator in which compressed refrigerant is flashed and have the baffle positioned downstream from the evaporator. The heat in the air is transferred to the evaporating refrigerant in the evaporator, thereby cooling the air. As the air is cooled, water in the air may condense forming small droplets, like a mist, in the air stream. When the air stream containing the small water droplets passes around a baffle, the small droplets may accumulate on the downstream side of the baffle in a region of turbulent or vortex like air flow. In this area, the small droplets may agglomerate and form larger drops as the air moves through the HVAC system. The larger drops may be carried by the air flow and out of vents into the passenger compartment of a vehicle.
It would be advantageous to provide an HVAC system having a linear control relationship between the position of the temperature control and the output temperature.